Damn, what a cool OST! One of my favorites along with X and 5 precisely because the gameplay is more and more refined, the visuals have reached their peak, and the bosses are a lot of fun. The OST in this one and in 5 is a show on its own, and the pacing is perfect. The final boss in this one is one of the coolest, if not the coolest, in the series, I just love the Dr. Willy vibes.